Well drill



March 17, 1936. WRIGHT 2,034,074

WELL DRILL Filed Oct. 6, 1934 f/VVENTOR JESSE C. Mawa Patented 17, 1936 WELL mum.

Jesse C. Wright,

Los Angeles, Calif.

Application October 6, 1934, Serial No. 747,188

. Claims.

This invention relates to'a well drilling "tool and relates more particularly to a well drill for use in the rotary method of drilling. A general object of the invention is to provide a simple,

a practical and efiective rotary well drill adapted for the enlarging of pilot bores.

Another object of the invention is to provide an effective and dependable means for locking a replaceable cutter head or bit on the shank of o 8. W811 tOOl.

Another object of the invention is to provide a well drill including a pilot bit threaded on a shank and a simple, convenient means for locking the pilot bit against unthreading from the 15 shank.

Another object of the invention is to provide a well drill of the character mentioned comprising a pilot bit for entering a pilot hole or. bore and a reaming cutter for enlarging the bore, said 20 bit and cutter being formed and related to drill or form an enlarged bore that is straight and vertical.

A further object of the invention is to provide awell drill of the character mentioned that 35 is inexpensive of manufacture and that embodies a simple, one piece shank.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred 30 form and application of the invention, throughout which description reference may be made to the accompanying drawing, in which:

Fig. .1 is a side elevation of the drill of the present invention, operating in a well bore, illus- 35 trating one quarter in longitudinal cross section. Fig. 2 is a transverse detailed sectional viewtaken as indicated by line 22 on Fig. 1. Fig. 3 is a bottom elevation of the drill and Fig. 4 is a transverse detailed sectional view taken as indicated 40 by line 44 on Fig. 1, illustrating the means for locking the pilot bit onto the shank.

The drill of the present invention includes, generally, a shank ill, a pilot cutter or pilot bit H on the lower end of the shank, means l2 for 45 looking the pilot bit H against detachment from the shank l0, and a bore enlarging or reaming cutter 13 on the shank In above the pilot cutter ll.

The shank In is provided to carry the pilot bit II and the reaming cutter'l3' and in accordance with the invention may be a simple one piece or integral member. The shank Ill may be com paratively long and may be generally cylindrical. Suitable means is provided at the upper end 55 of the shank for facilitating-its connection with the drilling string. In the particular construction illustrated in the drawing a tapered screw-threaded pin M is provided on the upper end of the shank ill to connect the shank with the string. An annular enlargement or flange I5 is provided on the shank Ill at some distance below its upper end. The lower end or face of the flange i5 forms an annular downwardly facing shouldenlli. A suitably tapered threaded portion I1 is provided on the shank l0 below the shoulder IE to carry the cutter l3. The'lower portion iii of the shank occurring below the threaded portion I1 is of reduced diameter and may be stepped or graduated as illustrated in Fig. l of the drawing. A tapered screw-threaded pin 19 projects from the lower endof the shank in to carry the pilot bit II. A downwardly facing annular shoulder 20 is provided at the upper end of the pin I9. In the preferred construction the pin [9 has a plain or unthreaded portion 2| between the shoulder 20 and its thread. The pilot cutter or pilot bit H is adapted to operate in a previously formed pilot hole or bore B to guide the drill whereby the reaming cutter l3 enlarges the bore to provide a straight vertical well bore W of the desired diameter. It is to be understood, of course, that the pilot bit H may be operated to drill into the formation to form its own pilot bore B. The pilot bit H includes ashoe or body 22 having a. threaded socket 23' receiving'the pin IQ of the shank. The pilot bit body 22 is adapted to be threaded on the pin 19 to a position where its upper end bears upwardly against the shoulder 20. The upper end portion of the socket 23 which surrounds the shank portion 2! is preferably plain or unthreaded. Thebit body 22 may have a downwardly tapering periphery and lower end.

The pilot bit ll includes guiding, and cutting parts adapted to-engage the wall of the pilot bore B to guide the drill, said cutting parts being operatable to drill a pilot bore when a previously formed pilot bore has not been drilled. The guiding and cutting parts of the pilot bit II are preferably in the form of blades 24 projecting downwardly from the lower end of the bit body 22 and projecting radially outwardly "from the body. In the particular construction illustrated in the drawing there are four equally spaced blades 24 provided on the pilot bit. The blades 24 are preferably comparatively long to extend downwardly from acfiacent the upper end of the body 22 to points some distance below the lower end of the body. The blades 24- have straight substantially vertical reaming and guiding edges 55 25 for engaging the wall of the pilot bore. The long reaming and guiding edges 25 of the circumferentially spaced blades 24 efiectively stabilize and guide the drill. The lower ends of the blades 24 are formed and shaped to effectively drill through the formation when the drill is operated to form its own pilot bore, and when the pilot bit I I reaches the lower end of a previously formed pilot bore. The lower end portions of the blades 24 are .curved forwardly relative tothe direction of rotation of the drill and have suitable cutting edges 28. I

The lower end portions of the blades 24 are notched or provided with upwardly extending notches. There is preferably one notch provided in the lower edge of each blade 24 at a point spaced between the inner and outer ends of the blade. The notches 21 in one pair of diametrically opposite blades 24 are closer tothe central longitudinal axis of the drill than the notches 28 in the other pair of diametrically opposite blades. The notches 21 separate ordivide the lower portion of the first mentioned blades 24 into outer teeth 29 and inner teeth 30. In a like manner the notches 28 in the said other blades 24 divide the lower portions of the blades into outer teeth 3I and inner teeth 32. The inner teeth 38 extend inwardly to join one another at the central longitudinal axis of the drill to cut away the formation at the center of the bore. The inner teeth 32 of the other blades are spaced from the central longitudinal axis of the drill to act-0n the formation in the path of the notches 21. The outer teeth 29 are preferably of sumcient width to cut away the formation left by the notches 28. The cutting blades 24 formed and related as just described are particularly rapid and efllcient in operation when the drill is operated to form its own pilotbore.

Under some conditions of operation the previously formed pilot bore 13 may have an enthe pilot bit II against unthreading and detach-.

ment from the shank under all operating conditions. It is a feature of the invention that the lock means I2 is such that the pilot bit II may be easily threaded on the pin I9 to a position where its upper end clamps against the shoulder 28 and may then be quickly locked in the desired position.

The lock means l2 includes or provides a plurality of circumferentially spaced sockets 33 in the pin I9. In practice ,it has been found desirable to provide three. equally spaced sockets in the pin of the shank. The sockets 33 are preferably provided in the unthreaded upper portion 2| of the pin, it being understood that the sockets may be provided at other points in the pin if desired or found practical. The lock means I2 further provides openings 34 in the wall of the pilot bit body 22. The openings 34 are circumferentially spaced in a horizontal plane and are located so that they are in the same horizontal plane as the sockets 33 when the upper end of the bit body 22 is engaging or is immediately adjacent the shoulder 28.

In accordance with the invention the openings 34 are related to the sockets 33 so that one of them will register with a socket 33 when the bit body 22 is in any possible rotative position on the pin I9 with its upper end engaging or adjacent the shoulder 20. This relationing of the openings 34 to the sockets 33 is preferably accomplished by horizontally elongating the openings and by providing more openings 34 than there are sockets 33. Thus where there are three sockets 33 it may be desirable to provide four equally spaced horizontally elongated openings 34. The horizontal length of the openings 34 is sufficient to insure the registration of one of the openings with a socket 33 when the pilot bit I I is threaded to the required position on the pin I9. By providing more openings 34 than there are sockets 33 it does not become necessary to horizontally elongate the openings 34 to such an extent as to materially weaken the bit body 22.

A lock member 35 is adapted to be inserted in the exposed socket 33 to extend into the registering opening 34 to lock the pilot bit I I against unthreading from the shank III. In the simple preferred formof the invention illustrated in the drawing the sockets 33 are threaded and the lock member 35 is in the form of a screw adapted to be threaded into the exposed socket 33 to project into the registering opening 34. The set screw or look member 35 is proportioned so that its head or outer projecting portion is entirely within the opening 34. The outer portion or head of the lock member 35 is provided with a polygonal socket 36 to facilitate the threading of the member into the socket 33. The screw or look member 35 threaded into a socket 33 and projecting into an opening 34 dependably locks the pilot bit II against unthreading from the shank I3 under all conditions of operation of the drill.

The bore enlarging or reamingcutter I3 is removably attached to the shank I0 above the pilot bit II to act on the earth formation at the upper end ofthe pilot bore II and provide or drill the enlarged bore W. The reaming cutter I3 includes a body or shoe 31 threaded on the portion I1 of the shank to bear or clamp upwardly against the shoulder I8. Prior to the arrangement of the pilot bit II on the shank III the shoe 31 of the reaming cutter is adapted to be passed over the lower portion of the shank and threaded on the shank portion I1. While I have not shown the reaming cutter I3 locked on the shank III it is apparent that it may be locked in place by a means similar to the means I2 described above. The reaming cutter I3 includes cutting parts in the form of blades 38 projecting from the shoe 31. There may be four circumferentially spaced blades 38 projecting downwardly and outwardly from the shoe 31. The blades 38 have lower cutting edges 39 which act on the earth formation at the shoulder S between the pilot bore B and the enlarged bore W. The lower cutting edges 39 of the reaming blades may be straight and horizontal as illustrated in' Fig. 1. The blades 38 are provided with comparatively long reaming edges 40 for acting on the wall of .the well bore W.

The drill is provided with means for handling the circulation fluid usually employed in the rotary method of well drilling. A central longitudinal fluid passage 4| extends through the shank from the upper end of the-pin I4 to the lower end of the pin I 9. The body. 22 of the pilot bit has a chamber 42 at the lower end of the socket 23 to receive the circulation fluid from the passage 4!. Discharge openings or ports 43 are provided in the lower end wall of the bit body 22 to discharge the circulation fluid downwardly from the chamber 42. The ports 43 are preferably located to discharge into the well at points between the spaced blades 24.

It is believed that the operation of the well drill will be readily understood from the foregoing detailed description. When employed to enlarge a previously drilled pilot bore B the pilot bit ll enters the pilot bore and operates therein to guide the drill. The long reaming edges 25 of the pilot bit blades engage the wall of the pilot bore B to steady the drill during operation and to guide the drill to make a vertical hole. As the shoulder S occurring between the pilot bore B and the enlarged portion W of the well bore may be comparatively narrow the reaming cutter I3 is rapid in its cutting action. The downwardly feeding pressures or drill pressures applied to the drill are concentrated on the portions of the blades 38 acting on the shoulder S so that a high cutting pressure is exerted per lineal unit of the cutting edges 39; The circumferential spacing of the blades 24 and the blades 38 insures the steady smooth operation of the drill. When the drill is employed to cut its own pilot bore the teeth 29, 30, 3| and 32 of the pilot bit blades act on the formation at the bottom of the bore to drill the pilot hole. The spacing and relating of the teeth is such that they are rapid and eifective in their drilling action. When the pilot bit I I is employed to drill the pilot bore B the blades 38 of the reaming cutter enlarge the bore to the desired size.

The means l2 for locking the pilot bit H on the shank I is simple and inexpensive and dependably holds the pilot bit against detachment.

When attaching the pilot bit II to the shank it may be freely threaded on the pin l9 to clamp upwardly against the shoulder 20 with the desired force. Because of the relationship between the sockets and the openings 34 an opening 34 registers with a socket 33 regardless of the rotative position assumed by the pilot bit when finally threaded on the pin IS. The lock member or set screw 35 may be threaded into the exposed socket 33 to project into the registering opening 34. The lock member 35 operates to prevent the accidental or unintentional unthreading of the pilot, bit from the shank. When it becomes desirable or necessary to remove the, pilot bit I I from the shank the lock member 35 may be unthreaded from the socket 33 whereupon the pilot bit may be unthreaded from the pin IQ of the shank.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific form and application herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A well drill including a shank having circumferentially spaced sockets, a cutter threaded on the shank having circumferentially spaced openings one of which registers with a socket when the cutter is threaded to its position on the shank, and a lock member inserted in the said socket to project into and cooperate with the said opening to lock the cutter against unthreading 2. A well drill including a shank having circumferentially spaced sockets, a bit threaded on the lower end of the shank having circumferentially spaced openings, one of which will register with a socket regardless of the rotative position of the bit when the bit is in its proper longitudinal position on the shank, and a lock member adapted to be inserted in the said socket to project into the said opening to lock the bit against unthreading.

3. A well drill including a'shank having circumferentially spaced sockets, a shoulder on the shank, a cutter threaded on the shank to bear against the shoulder having a plurality of circumferentially spaced openings, one of which will register with a socket regardless of the rotative position assumed by the cutter when bearing against the shoulder, and a screw threaded in the said socket to project into the opening registering with the socket to lock the cutter against unthreading.

4. A well drill including a shank having circumferentially spaced sockets, a bit threaded on the lower end of the shank having circumferentially spaced openings, the openings being circumferentially elongated and related to the sockets so that one of them will register with a socket regardless of the rotative position of the bit when the bit is in its proper longitudinal position on the shank, and a lock member adapted to be inserted in the said socket to project into the said opening to lock the bit against unthreading.

5. A well drill including a shank having a threaded lower portion, a downwardly facing "shoulder on the shank, there being a plurality of circumferentially spaced sockets in the shank adjacent the shoulder, a bit threaded on the lower portion of the shank to bear upwardly against the shoulder, the bit having a plurality of circumferentially spaced openings one of which will register with a socket regardless of the rotative position assumed by the bit when bearing against the shoulder, and a lock part threaded into said socket to extend into the said opening to lock the bit against unthreading.

JESSE C. WRIGHT. 

